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        <h2 id="网格视图（Sliver）"><a href="#网格视图（Sliver）" class="headerlink" title="网格视图（Sliver）"></a>网格视图（Sliver）</h2><figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br></pre></td><td class="code"><pre><span class="line">class SliverDemo extends StatelessWidget &#123;</span><br><span class="line">  @override</span><br><span class="line">  Widget build(BuildContext context) &#123;</span><br><span class="line">    return Scaffold(</span><br><span class="line">      appBar: AppBar(</span><br><span class="line">        title: Text(&#39;SliverDemo&#39;),</span><br><span class="line">      ),</span><br><span class="line">      body: CustomScrollView(</span><br><span class="line">        slivers: &lt;Widget&gt;[</span><br><span class="line">          SliverGrid(</span><br><span class="line">            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(</span><br><span class="line">              crossAxisCount: 2,</span><br><span class="line">              crossAxisSpacing: 8,</span><br><span class="line">              mainAxisSpacing: 8,</span><br><span class="line">              childAspectRatio: 1 &#x2F;&#x2F; 控制该网格视图显示的比例</span><br><span class="line">            ),</span><br><span class="line">            delegate: SliverChildBuilderDelegate(</span><br><span class="line">              (BuildContext context, int index)&#123;</span><br><span class="line">                return Container(</span><br><span class="line">                  child: Image.network(</span><br><span class="line">                    posts[index].imageUrl,</span><br><span class="line">                    fit: BoxFit.cover,</span><br><span class="line">                  ),</span><br><span class="line">                );</span><br><span class="line">              &#125;,</span><br><span class="line">              childCount: posts.length</span><br><span class="line">            ),</span><br><span class="line">          ),</span><br><span class="line">        ],</span><br><span class="line">      ),</span><br><span class="line">    );</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p><img src="https://upload-images.jianshu.io/upload_images/16731485-9debf374656acd46.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240" alt="预览"></p>
<h3 id="SliverPadding（内边距）"><a href="#SliverPadding（内边距）" class="headerlink" title="SliverPadding（内边距）"></a>SliverPadding（内边距）</h3><p><code>SliverPadding</code>主要为了给<code>SliverGrid</code>创造内边距</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><span class="line">class SliverDemo extends StatelessWidget &#123;</span><br><span class="line">  @override</span><br><span class="line">  Widget build(BuildContext context) &#123;</span><br><span class="line">    return Scaffold(</span><br><span class="line">      appBar: AppBar(</span><br><span class="line">        title: Text(&#39;SliverDemo&#39;),</span><br><span class="line">      ),</span><br><span class="line">      body: CustomScrollView(</span><br><span class="line">        slivers: &lt;Widget&gt;[</span><br><span class="line">          SliverPadding(</span><br><span class="line">            padding: EdgeInsets.all(8),</span><br><span class="line">            sliver: SliverGridDemo(),</span><br><span class="line">          )</span><br><span class="line">        ],</span><br><span class="line">      ),</span><br><span class="line">    );</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br></pre></td><td class="code"><pre><span class="line">class SliverGridDemo extends StatelessWidget &#123;</span><br><span class="line">  @override</span><br><span class="line">  Widget build(BuildContext context) &#123;</span><br><span class="line">    return SliverGrid(</span><br><span class="line">      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(</span><br><span class="line">        crossAxisCount: 2,</span><br><span class="line">        crossAxisSpacing: 8,</span><br><span class="line">        mainAxisSpacing: 8,</span><br><span class="line">        childAspectRatio: 1 &#x2F;&#x2F; 控制该网格视图显示的比例</span><br><span class="line">      ),</span><br><span class="line">      delegate: SliverChildBuilderDelegate(</span><br><span class="line">        (BuildContext context, int index)&#123;</span><br><span class="line">          return Container(</span><br><span class="line">            child: Image.network(</span><br><span class="line">              posts[index].imageUrl,</span><br><span class="line">              fit: BoxFit.cover,</span><br><span class="line">            ),</span><br><span class="line">          );</span><br><span class="line">        &#125;,</span><br><span class="line">        childCount: posts.length</span><br><span class="line">      ),</span><br><span class="line">    );</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p><img src="https://upload-images.jianshu.io/upload_images/16731485-6beeac267983973d.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240" alt="预览"></p>
<h3 id="SliverSafeArea（安全区）"><a href="#SliverSafeArea（安全区）" class="headerlink" title="SliverSafeArea（安全区）"></a>SliverSafeArea（安全区）</h3><p>让该网格视图显示在不被手机装饰所遮挡的地方</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br></pre></td><td class="code"><pre><span class="line">class SliverDemo extends StatelessWidget &#123;</span><br><span class="line">  @override</span><br><span class="line">  Widget build(BuildContext context) &#123;</span><br><span class="line">    return Scaffold(</span><br><span class="line">      appBar: AppBar(</span><br><span class="line">        title: Text(&#39;SliverDemo&#39;),</span><br><span class="line">      ),</span><br><span class="line">      body: CustomScrollView(</span><br><span class="line">        slivers: &lt;Widget&gt;[</span><br><span class="line">          SliverSafeArea(</span><br><span class="line">            sliver: SliverPadding(</span><br><span class="line">              padding: EdgeInsets.all(8),</span><br><span class="line">              sliver: SliverGridDemo(),</span><br><span class="line">            ),</span><br><span class="line">          )</span><br><span class="line">        ],</span><br><span class="line">      ),</span><br><span class="line">    );</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<h3 id="SliverList-ClipRRect（图片圆角）"><a href="#SliverList-ClipRRect（图片圆角）" class="headerlink" title="SliverList + ClipRRect（图片圆角）"></a>SliverList + ClipRRect（图片圆角）</h3><figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br></pre></td><td class="code"><pre><span class="line">class SliverListDemo extends StatelessWidget &#123;</span><br><span class="line">  @override</span><br><span class="line">  Widget build(BuildContext context) &#123;</span><br><span class="line">    return SliverList(</span><br><span class="line">      delegate: SliverChildBuilderDelegate(</span><br><span class="line">        (BuildContext context, int index)&#123;</span><br><span class="line">          return Padding(</span><br><span class="line">            padding: EdgeInsets.only(bottom: 32),</span><br><span class="line">            child: ClipRRect(</span><br><span class="line">              borderRadius: BorderRadius.circular(12),</span><br><span class="line">              child: Stack(</span><br><span class="line">                children: &lt;Widget&gt;[</span><br><span class="line">                  AspectRatio(</span><br><span class="line">                    aspectRatio: 16&#x2F;9,</span><br><span class="line">                    child: Image.network(</span><br><span class="line">                      posts[index].imageUrl,</span><br><span class="line">                      fit: BoxFit.cover,</span><br><span class="line">                    ),</span><br><span class="line">                  ),</span><br><span class="line">                  Positioned(</span><br><span class="line">                    top: 32,</span><br><span class="line">                    left: 32,</span><br><span class="line">                    child: Column(</span><br><span class="line">                      mainAxisAlignment: MainAxisAlignment.start,</span><br><span class="line">                      children: &lt;Widget&gt;[</span><br><span class="line">                        Text(</span><br><span class="line">                          posts[index].title,</span><br><span class="line">                          style: TextStyle(</span><br><span class="line">                            fontSize: 20,</span><br><span class="line">                            color: Colors.white</span><br><span class="line">                          ),</span><br><span class="line">                        ),</span><br><span class="line">                        Text(</span><br><span class="line">                          posts[index].author,</span><br><span class="line">                          style: TextStyle(</span><br><span class="line">                            fontSize: 13,</span><br><span class="line">                            color: Colors.white</span><br><span class="line">                          ),</span><br><span class="line">                        )</span><br><span class="line">                      ],</span><br><span class="line">                    ),</span><br><span class="line">                  )</span><br><span class="line">                ],</span><br><span class="line">              )</span><br><span class="line">            ),</span><br><span class="line">          );</span><br><span class="line">        &#125;,</span><br><span class="line">        childCount: posts.length</span><br><span class="line">      ),</span><br><span class="line">    );</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<p><img src="https://upload-images.jianshu.io/upload_images/16731485-aee33d02f0c06439.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240" alt="预览"></p>
<h2 id="SliverAppBar（应用工具栏）"><a href="#SliverAppBar（应用工具栏）" class="headerlink" title="SliverAppBar（应用工具栏）"></a>SliverAppBar（应用工具栏）</h2><p>类似于<code>AppBar</code>的导航栏，在默认状态下，我们向下移动就会隐藏导航栏；而想要显示导航栏，必须滑动到页面顶部。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br></pre></td><td class="code"><pre><span class="line">class SliverDemo extends StatelessWidget &#123;</span><br><span class="line">  @override</span><br><span class="line">  Widget build(BuildContext context) &#123;</span><br><span class="line">    return Scaffold(</span><br><span class="line">      body: CustomScrollView(</span><br><span class="line">        slivers: &lt;Widget&gt;[</span><br><span class="line">          SliverAppBar( &#x2F;&#x2F; 类似于APPBar，但滑动到一定程度导航栏会隐藏</span><br><span class="line">            title: Text(&#39;SliverDemo&#39;),</span><br><span class="line">            centerTitle: true, &#x2F;&#x2F; 居中标题</span><br><span class="line">            &#x2F;&#x2F; pinned: true, &#x2F;&#x2F; 将此属性设为true的话，导航栏就会固定在页面上部</span><br><span class="line">            </span><br><span class="line">            &#x2F;&#x2F; 此属性默认为false，我们必须滑到页面顶部，导航栏才会显现；</span><br><span class="line">            &#x2F;&#x2F; 若为true，不管在什么位置，只要稍微向上滑动一点，导航栏就会显现</span><br><span class="line">            &#x2F;&#x2F; floating: true, </span><br><span class="line">          ), </span><br><span class="line">          SliverSafeArea( &#x2F;&#x2F; 安全区</span><br><span class="line">            sliver: SliverPadding( &#x2F;&#x2F; Sliver视图的内边距</span><br><span class="line">              padding: EdgeInsets.all(8),</span><br><span class="line">              sliver: SliverListDemo(),</span><br><span class="line">            ),</span><br><span class="line">          )</span><br><span class="line">        ],</span><br><span class="line">      ),</span><br><span class="line">    );</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<h2 id="待渐进动画的可伸缩空间"><a href="#待渐进动画的可伸缩空间" class="headerlink" title="待渐进动画的可伸缩空间"></a>待渐进动画的可伸缩空间</h2><figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br></pre></td><td class="code"><pre><span class="line">SliverAppBar( &#x2F;&#x2F; 类似于APPBar，但滑动到一定程度导航栏会隐藏</span><br><span class="line">  &#x2F;&#x2F; title: Text(&#39;SliverDemo&#39;),</span><br><span class="line">  centerTitle: true, &#x2F;&#x2F; 居中标题</span><br><span class="line">  &#x2F;&#x2F; pinned: true, &#x2F;&#x2F; 将此属性设为true的话，导航栏就会固定在页面上部</span><br><span class="line"></span><br><span class="line">  &#x2F;&#x2F; 此属性默认为false，我们必须滑到页面顶部，导航栏才会显现；</span><br><span class="line">  &#x2F;&#x2F; 若为true，不管在什么位置，只要稍微向上滑动一点，导航栏就会显现</span><br><span class="line">  &#x2F;&#x2F; floating: true, </span><br><span class="line"></span><br><span class="line">  expandedHeight: 178, &#x2F;&#x2F; 可伸缩控件的高度</span><br><span class="line">  flexibleSpace: FlexibleSpaceBar( &#x2F;&#x2F; 可伸缩空间的具体样式</span><br><span class="line">    title: Text(</span><br><span class="line">      &#39;Ninghao Flutter&#39;.toUpperCase(),</span><br><span class="line">      style: TextStyle(</span><br><span class="line">        fontSize: 15,</span><br><span class="line">        letterSpacing: 3,</span><br><span class="line">        fontWeight: FontWeight.w400</span><br><span class="line">      ),</span><br><span class="line">    ),</span><br><span class="line">    background: Image.network( &#x2F;&#x2F; 背景</span><br><span class="line">      &#39;https:&#x2F;&#x2F;resources.ninghao.org&#x2F;images&#x2F;overkill.png&#39;,</span><br><span class="line">      fit: BoxFit.cover,</span><br><span class="line">    ),</span><br><span class="line">    centerTitle: true,</span><br><span class="line">  ),</span><br><span class="line">), </span><br></pre></td></tr></table></figure>
<p><img src="https://upload-images.jianshu.io/upload_images/16731485-6ae85f4d564219d6.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240" alt="预览"></p>

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